People are increasingly utilizing portable electronic devices, such as smart phones, tablet computers, wearable computing devices (e.g., smart watches), among others, for a variety of tasks. Many of these devices have at least one display/touch assembly that can include a display element (e.g., liquid crystal display (LCD), organic light-emitting diode (OLED), electronic ink (e-ink), etc.), a touch element (e.g., resistive, capacitive, surface acoustic wave, or infrared touchscreen, etc.), and an overlying transparent layer. This overlying layer, referred to as a “cover sheet,” “cover glass,” or “cover lens” is attached to the display/touch assembly by a process sometimes referred to as “optical bonding.” Optical bonding involves utilizing a clear adhesive to join one or more substrates of a display and/or touch element. Optical bonding can serve several different important functions for electronic devices. Optical bonding can significantly improve optical performance of the display element. For example, optical bonding can minimize the air gap between the cover sheet and display element and thus reduce the number of reflective surfaces of the electronic device's display element. Optical bonding may also reduce the light loss due to reflection. This can improve the viewing experience of the user while using less power consumption and thereby extending the battery life of the device. In addition, optical bonding can reduce parallax error and can produce a thinner product by eliminating or minimizing the air gap between the cover sheet and the display element.
After a cover sheet is optically bonded to a display and/or touch element, the cover sheet of the display/touch assembly (i.e., display element, touch element, and bonded cover sheet) can be utilized as a mounting surface for attaching the display/touch assembly to other components of the electronic device, such as cameras, ambient light detectors, infrared sensors, antennas, or housings or frames for printed circuit boards (PCBs), among other components. Typically these other components are bonded to the cover glass to help seal the components from moisture, dust, light, sound, etc. Optical bonding and bonding of the cover sheet to other device components thus provide a variety of benefits for electronic devices but certain conventional bonding techniques require extensive time and effort during the manufacturing process. This can delay assembly of the devices and increase the costs of production. Other conventional bonding processes may not require as much time and effort but assembled devices from such conventional processes may be more susceptible to damage from lens crack or delamination.